INA219.cpp

00001 #include "INA219.h"
00002 
00003 INA219::INA219(PinName sda, PinName scl, unsigned char adr) :
00004     _i2c(sda, scl)
00005 {
00006     _i2c.frequency(100000);
00007     _adr = adr;
00008 }
00009 
00010 bool INA219::detect(void)
00011 {
00012     _i2c.start();
00013     bool det = (1 == _i2c.write(_adr|1/*write address for reading*/));
00014     _i2c.stop();
00015     return det;
00016 }
00017 
00018 double INA219::getCurrent(void)
00019 {
00020     double d = 0.0;
00021     char r = 0x01;
00022     if (0 == _i2c.write(_adr, &r, sizeof(r), true))
00023     {
00024         char v[2] = {0};
00025         if (0 == _i2c.read(_adr, v, sizeof(v)))
00026         {
00027             int u = (int)((((short)v[0]) << 8) + (unsigned char)v[1]) * 10; // uV
00028             int i = u * 2/*0.5ohm*/;
00029             d = 1e-6 * i;
00030         }
00031     }
00032     else 
00033     {
00034         _i2c.stop();
00035     }
00036     return d;
00037 }
00038 
00039 double INA219::getVoltage(void)
00040 {
00041     double d = 0.0;
00042     char r = 0x02;
00043     if (0 == _i2c.write(_adr, &r, sizeof(r), true))
00044     {
00045         char v[2] = {0};
00046         if (0 == _i2c.read(_adr, v, sizeof(v)))
00047         {
00048             int u = (int)(((((short)v[0]) << 8) + (unsigned char)v[1]) >> 3) * 4; // mV
00049             d = 1e-3 * u;
00050         }
00051     }
00052     else 
00053         _i2c.stop();
00054     return d;
00055 }